diff --git a/libsolidity/ast/AST.h b/libsolidity/ast/AST.h
index 11b86d3b7..5e88872cc 100644
--- a/libsolidity/ast/AST.h
+++ b/libsolidity/ast/AST.h
@@ -504,23 +504,6 @@ public:
 		m_abstract(_abstract)
 	{}
 
-	ContractDefinition(
-		int64_t _id,
-		SourceLocation const& _location,
-		boost::filesystem::path const& _jsonSourceFile
-	):
-		ContractDefinition{
-			_id,
-			_location,
-			{},			// name
-			{},			// StructuredDocumentation
-			{},			// InheritanceSpecifier[]
-			{}			// body
-		}
-	{
-		m_jsonSourceFile = _jsonSourceFile;
-	}
-
 	void accept(ASTVisitor& _visitor) override;
 	void accept(ASTConstVisitor& _visitor) const override;
 
@@ -577,14 +560,11 @@ public:
 	/// @returns the next constructor in the inheritance hierarchy.
 	FunctionDefinition const* nextConstructor(ContractDefinition const& _mostDerivedContract) const;
 
-	std::optional<boost::filesystem::path> jsonSourceFile() const noexcept { return m_jsonSourceFile; }
-
 private:
 	std::vector<ASTPointer<InheritanceSpecifier>> m_baseContracts;
 	std::vector<ASTPointer<ASTNode>> m_subNodes;
 	ContractKind m_contractKind;
 	bool m_abstract{false};
-	std::optional<boost::filesystem::path> m_jsonSourceFile {std::nullopt};
 
 	util::LazyInit<std::vector<std::pair<util::FixedHash<4>, FunctionTypePointer>>> m_interfaceFunctionList[2];
 	util::LazyInit<std::vector<EventDefinition const*>> m_interfaceEvents;
diff --git a/libsolidity/interface/CompilerStack.cpp b/libsolidity/interface/CompilerStack.cpp
index 1c327cdce..fe4a68c16 100644
--- a/libsolidity/interface/CompilerStack.cpp
+++ b/libsolidity/interface/CompilerStack.cpp
@@ -277,14 +277,6 @@ bool CompilerStack::parse()
 void CompilerStack::loadMissingInterfaces(int64_t _baseNodeID)
 {
 	vector<ASTPointer<SourceUnit>> importedSources;
-	for (ASTPointer<SourceUnit> importedSourceUnit: importedSources)
-	{
-		Source source;
-		source.ast = importedSourceUnit;
-		auto const name = "__imported_interface_" + to_string(importedSourceUnit->id());
-		// TODO: maybe we want to make sure this isn't used already
-		m_sources[name] = move(source);
-	}
 	for (auto const& sourcePair: m_sources)
 	{
 		ASTPointer<SourceUnit> const& source = sourcePair.second.ast;
@@ -311,7 +303,7 @@ void CompilerStack::loadMissingInterfaces(int64_t _baseNodeID)
 						_baseNodeID++,
 						SourceLocation{},
 						source->licenseString(),
-						vector{ jsonContract }
+						vector<ASTPointer<ASTNode>>{ jsonContract }
 					);
 					importedSources.push_back(importedSource);
 				}
@@ -326,6 +318,15 @@ void CompilerStack::loadMissingInterfaces(int64_t _baseNodeID)
 			}
 		}
 	}
+
+	for (ASTPointer<SourceUnit> importedSourceUnit: importedSources)
+	{
+		Source source;
+		source.ast = importedSourceUnit;
+		auto const name = "__imported_interface_" + to_string(importedSourceUnit->id());
+		solAssert(m_sources.count(name) == 0, "");
+		m_sources[name] = move(source);
+	}
 }
 
 void CompilerStack::importASTs(map<string, Json::Value> const& _sources)
diff --git a/libsolidity/parsing/Parser.cpp b/libsolidity/parsing/Parser.cpp
index 47a216a09..8b519d2b3 100644
--- a/libsolidity/parsing/Parser.cpp
+++ b/libsolidity/parsing/Parser.cpp
@@ -316,7 +316,8 @@ ASTPointer<ContractDefinition> Parser::parseInterfaceDefinition()
 		nodeFactory.markEndPosition();
 		expectToken(Token::Semicolon);
 
-		return nodeFactory.createNode<ContractDefinition>(jsonSourceFileName);
+		auto fileName = make_shared<ASTString>(jsonSourceFileName.string());
+		return nodeFactory.createNode<ImportedContractDefinition>(name, fileName);
 	}
 
 	baseContracts = parseContractInheritanceList();